|The Climbing Club
|The Problem with Rappel Back-Ups Off Modern Leg-Loops
|Page 2 of 2|
|Author:||David Yount [ Thu Jun 17, 2010 5:15 pm ]|
|Post subject:||Re: The Problem with Rappel Back-Ups Off Modern Leg-Loops|
I far prefer a friction hitch rigged above the primary rappelling device, I use a Klemheist friction hitch. A friction hitch rigged below the primary rappelling device comes with too many limitations and challenges and also is missing several of the added advantages of a friction hitch rigged above the primary rappelling device. I use a friction hitch backup when I rappel almost every time I rappel.
If you do prefer to rig a backup friction hitch below your primary rappelling device it is fine to attach it to your leg loop. If your leg loop has the newer design of buckle that loosens quickly then it is best to attach the carabiner on the leg loop near the crotch, as the article illustrates. However, if you attach near the leg loop buckle there is a minor concern that the force may loosen the leg loop. If the leg loop loosens sufficiently then the friction hitch may not function as it is intended, rendering it nearly useless. But, I find it less than unlikely that the leg loop will be fully compromised. I don't believe there is sufficient space between the leg loop and the primary rappelling device for the force from the friction hitch to fully unthread the webbing thru the leg loop buckle. As well, as was wisely pointed out, the webbing on leg loops is double backed and bar tacked when used with these newer fast releasable buckles, preventing the webbing from inadvertently fully unthreading thru the buckle.
To summarize, if you choose to rig a friction hitch below the rappel device and you carabiner to the leg loop near the buckle and you have a newer style non-double back buckle, then there is a minor concern that if the friction hitch is loaded then the leg loop buckle may loosen somewhat. Worst case is the friction hitch ends up jamming into the bottom face of the rappel device and the climber makes an unintended rappel (fairly slowly or maybe even up to moderately fast).
Manually double back buckles used on leg loops is somewhat out of fashion, convenience (with no increased danger) will always win. Evnetually all adjustable leg loops will incorporate these newer buckles. They are not unsafe.
Individual pockets on Daisy Chains are not nearly as strong as webbing loops, they are designed for "body weight" applications. And, I have used Daisy Chains for rappel backup rigging for decades, as well as anchoring at belay stances. I replace my Daisy Chains when I see significant stitch stress and stretch; takes over 4000 pitches of climbing, for me. Further beware there is the possibility that if your Daisy Chain pocket rips open that when the force hits the next pocket, that pocket will pull open, and theoretically this sequence many continue such that your carabiner reaches the final loop of webbing..... and depending on how you've clipped, your biner may _NOT_ be rigged to the last loop. There is a animation (on petzl?) of exactly how this death magic occurs. Further, if you clip incorrectly into a single pocket, and that pocket fails, then your biner will be completely free, absolute system failure.
I love Daisy Chains, I know their intended uses, their manufacture and their failure modes. I use them accordingly.
|Page 2 of 2||All times are UTC - 8 hours [ DST ]|
|Powered by phpBB® Forum Software © phpBB Group